Timing control for circuits



March 31, 1936. F. W. HOBAN TIMING CONTROL FOR CIRCUITS Filed Oct. 31, 1932 INVENTOR f a yz'e/d h/flobm. BY

ATTORNEYS Patented Mar. 31, 1936 PATENT OFFICE TIMING ooN'raoL Fon CIRCUITS Fairfield W. Hoban, New York, N. Y., assignor to Falrfield Specialties Corporation, New York,

N. Y., a corporation of New York. ApplicationOctober 31, 1932, Serial No. 640,495

6 Claims.

My invention relates to means for controlling circuits, and the same has for its object to provide a simple, efiicient and reliable device, which is smooth and quick in its action, and which, when operated, controls the circuit to close or open the same for a predetermined period, the timing being retarded or delayed.

Another object of the invention is to provide a device of the character specified in which the retarding means for controlling the circuit constitutes an electromagnetically operated dashpot capable of operating in a gaseous medium, such as air.

Another object of the invention is to provide a a device of the character specified in which the circuit of the electromagnetic or retarding means is automatically controlled by the operation of the device, and preferably controlled electromagnetically.

Another object of the invention is to provide a device of the character specified in which the re-= tarded movable element or piston of the electro magnetic means thereof is tree to control "the electromagnetic means at one end of the path of travel of said element and to control another circuit at the other end oi the path of travel thereof.

Another object of the invention to provide a device of the character specified in which the retarded movable member of the dashpot is to move without appreciable retardation at the beginning and the end or its bacir and i'orth movement to quickly open and close the circuit to be controlled.

Another object of the invention is to provide a device of the character specified in whichprovi= sion is made for controlling or predetermining the timing or duration of operation of the cir cult to be controlled.

Other objects will in part be obvious and in part be pointed out hereinafter.

In the accompanying drawing:

Figure 1 is a front elevation of one form oi device constructed according to and embodying my said invention, the same being illustrated, as one example of its use, in association with a device the circuit of which is to be controlled;

Fig. 2 is a side elevation thereof;

Fig. 3 is a plan thereof;

Fig, 4 is a sectional view on the line 4t oi Fig. 1; and

Fig. 5 is a sectional view on the line 5-4.5 of Fig. 1.

My invention is adapted generally for controlling circuits which are only energized from time to time or at intervals, and which when energized must be energized quickly and for a limited period, such as for a few seconds, and then automatically deenergized. As one example of such use, I have illustrated my 5 device It] in association with an electri' cal apparatus ii for separating good or genuine coins from spurious devices or tokens for use in vending machines, change making machines, slot machines and coin operated appara- 1o tus of various kinds. The particular type of apparatus I2 illustrated is similar to that disclosed and claimed in my copending application Serial No. 517,222, filed February 20, 1931. In such apparatus, the coins or devices are inserted into 15 the chute l4 and pass gravitationally through a pair of fluctuating magnetic fields produced by the coils it. The fields act differentially on the coins or tokens and eventually effect by deflection the separation of the genuine from spurious devices. As such coin separating apparatus is only used at intervals, it is necessary to open the circuit thereof when the same is not in use, and to close said circuit the instant the coin is inserted, and to open the circuit as soon as the coin passes the fields. As the distance of travel I f the coin or tokens is very short, the time of passage oi the coin being substatially instantaneous, a circuit control is required having a speed of operation or timing of the same order as that reqid'ed for the coin to pass through the chute.

The device it for effecting results such as above outlined is of the type comprising a solenoid or electromagnetic coil l8 disposed about 35 the upper end or a tube 20 constituting the cylinder of a dashpot. A piston 22, constituting the magnetic armature or core, is slidably disposed in the cylinder 20, The tube 20 may be composed of any non-magnetic material, such as brass or 40 insulating material. The upper end of the tube til is sealed by a plug 24 of iron.

The circuit of the coil I8 is controlled by the contacts 26 and 28. The contact 26 is carried upon an electrically conductive metallic U-shaped 5 bracket 30 carried by an insulating member 32 secured about the upper end of the tube 20. The contact 28 is carried by an electrically conductive leaf spring 34 secured at one end to the member 32 and extending horizontally under bracket 30, 50 the leaf spring being biased to close the circuit at 2628. The leaf spring 34 is normally held depressed to open the circuit by a detent 36 pivoted at 38 on the member 32, extending through an opening 40 in spring 34 and adapted to engage the latter to hold it depressed. The detent 88 is normally held in engaging position, as shown, by a spring 42.

The detent 38 may be retracted to close the circuit of the solenoid l8 by any suitable means. In the application of the invention disclosed, the pivot 88 of the detent is provided with a rearwardly extending arm 44 insulated from the detent by insulation 48, the arm 44 extending through slots in the chute l4, and being disposed in the path of movement of the coins or devices. When such coin or device is inserted into the chute, the arm 44 is mechanically depressed thereby, releasing detent 88 and allow ing the contacts 28 and 28 to engage to energize the electromagnet l8. After the coin passes arm 44, the detent 88 is returned by spring 42 to position to lock the leaf spring when the latter is again depressed in the manner hereinafter described.

For eii'ecting the separation of the contacts 28 and 28 to open the circuit of the coil I8, I preferably employ the magnetism of the coil itself, this magnetism becoming eil'ective only when the core piston 22 is drawn by coil l8 into its uppermost position. For thus depressing the contact spring 84, I provide the spring with a magnetic armature 48 disposed above the magnetic plug 24. When the coil I8 is initially energized the magnetic effect on armature 48 is less than that required to depress spring 84, but when the piston 22 reaches its upp'ermost position the increase in core mass renders the magnetic eflect sufficient to draw down the spring 84, and cause the same to be locked in open circuit position by detent 88.

The control of the circuit of the coils I8 is effected at the end of the cylinder 28 remote from plug 24, a position for rendering the piston 22 available for controlling such circuit. For this purpose an insulating support 58 is secured about the lower end of the tube 20. Contacts 52 and 54 are mounted on this support, the contact 54 being carried on the free end of a leaf spring 58 secured at its opposite end to the member 58. The spring 58 extends horizontally below member 58 and is biased to close the circuit 52-54. The piston 22 is provided with an insulating nose 58 adapted to engage the spring 58 to retain the same in depressed open-circuit position, the weight of the piston effecting this result. The member 58 is provided with depending separated angle portions 88 serving to support and limit the downward movement of the spring 58 under the weight of the piston 22. When the coil I8 is energized as above described the piston 22 is lifted, releasing the spring 58 and allowing the contacts 52 and 54 to engage to close the circuit l8. Upon deenergization of the coil l8 as above described the piston drops and again opens the circuit at 52-54.

The current to coils i 8 and i8 is preferably supplied from a source of alternating current through leads 82 and 84, the lead 82 being connected to a terminal 88 in circuit with the spring 84 and contact 28, and the lead 84 being connected to a terminal 88 also connected to one side of the coil l8 through conductor 10. The opposite side of the coil I8 is connected by a conductor 12 with the contact 28.

The terminal 88 is also connected by a conductor I4 with the spring 58 and contact 54 in the circuit of the coils l8. One side of the coils I8 is connected through conductors 16 directly with the contact 52 and the other side thereof is connected through conductors 18 with the terminal 88. The tracing of the several circuits will be obvious.

The timing or the duration of closing of the circuit of the coils -I8 is determined by the dashpot action of the cylinder 20 and the piston 22, the duration of movement of the piston depending on the rate of flow of air from and into the cylinder 28 as the piston moves up and down. This rate of flow of air can be determined either by suitable calibration of the -clearance between the piston and the cylinders, the clearance being such as to render the piston easy sliding in the cylinder, or by provision of a suitable vent into the interior of the cylinder, such as by the passage 88 preferably extending from atmosphere axially through the nose 58 and through the piston 22, as shown. In the present invention, in order to variably control the timing of the piston movement, I preferably employ both leakage between the piston and the cylinder and leakage through vent 88 in the piston 22, or elsewhere, for controlling the rate of movement of the piston 22, and hence, the time of circuit closing.

In order to vary thetiming, the nose 58 is provided with an interiorly threaded tubular projection 82 extending through an opening in the spring 58, the projection extending beyond the lateral opening 88 leading into the passage 80, and between the angular portions 80. The projection 82 receives a screw valve 88 having a fine thread and provided with a tapered end 90 seating in the passage 88 and adapted to accurately adjust the extent of opening thereof or to completely close the same. In the present invention when the screw 88 completely closes the passage 88 the entire air leakage takes place between the piston and cylinder and the timing for the closing of the circuit at 52-54 is maximum, say three or four seconds. Upon slightly opening the passage 88 by a partial turn of the screw 88 the time interval can be reduced as required.

The cylinder 28 is also vented to atmosphere at 82; at a point substantially midway of its "length. The piston 22 has a. length such that,

when it is in lowermost position, its upper end is slightly below vent 92. Means are thus provided for speeding up the movement of the piston at the beginning and end of its movement to cause the contacts 52 and 54 to quickly disengage and engage for preventing sparking. Upon initial upward movement of the piston 22, the air in the cylinder 28 vents through opening 82, and

.no retarding effect is encounted, and the same is true when the piston clears the vent 92 upon downward movement thereof, the piston then rapidly accelerating to quickly open the contacts 52 and 54.

In operation, when the detent 88 is retracted, the coil l8 becomes energized and attracts the piston 22 which moves into the upper portion of the cylinder 20, at first rapidly and then with retardation, thereby closing circuit l8. As the piston approaches its uppermost position, it provides an iron core for the coil l8, increasing the magnetic effect for rendering the magnetism effective to draw down the armature 48 and open the circuit of the coil I8. Thereupon, the piston drops at first with a retarded effect, and then rapidly to open the contacts of the circuit of the device I 2.

By my invention the contacts of the circuit to be controlled may be instantaneously opened and closed by the movable element 22 of the dashpot which is subjected to the retarding eiiect determining the duration of closing 01' the circuit.

In my invention the piston 22 is free to move to control both the circuit l6 and the circuit of the electromagnet l8, the latter control being efiected electromagnetically without requiring engagement of the piston 22 with any moving parts, such as contacts.

The circuit timing control embodying my invention is smooth and accurate in operation under various conditions of use, and is particularly adapted for use in air without being upset by temperature or barometric changes.

The device is particularly adapted for use where the time interval for circuit closing is of the order of a few seconds, and by the adjustment provided the exact timing can be predetermined as desired.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A device of the character described comprising a solenoid including a cylinder and a magnetictily actuated core member therein, relatively movable contacts at the upper end of said solenoid for opening and closing the circuit of the solenoid and biased to move to closed position, the movable contact having a magnetic armature, and a releasable detent for retaining the movable contact in open circuit position, and normally biased to engage the movable contact, said detent automatically locking the movable contact in open circuit position upon attraction of said armature by the core member when the latter reaches the uppermost position thereof.

2. A circuit controlling device comprising a solenoid including a cylinder and a core member operating therein, said cylinder and said core member forming an air containing dashpot, means for controlling a load circuit operated by the core member at the beginning and at the end of movement thereof, and means for venting said cylinder during movement of said core member in both directions in the lower portion of the cylinder, said piston closing said venting means toretard the core member during movement thereof in both directions in the upper portion oi the cylinder.

3. A circuit controlling device comprising an electromagnetically operated dashpot including a cylinder and magnetically actuated core member operating therein, means for closing and opening the circuit of said dashpot, said means being operated to open said circuit by said core member in the uppermost position thereof, and means for controlling a load circuit operated in one direction upon actuation of said core member and in the other direction upon return of said core member to the lowermost position, the load circuit condition eflected upon actuation of the core member continuing for a period substantially coextensive with the duration of movement of the core member in both directions.

4. A circuit controlling device comprising a solenoid including a cylinder and a core member operating therein, a pair of contacts having the movable one thereof disposed in the path of said core member at the lower end of the solenoid to be retained in one position by the weight of the core member and to be released for movement to the other position upon actuation of said core member, said contacts remaining in the last named of the relative positions for a period substantially equal to the duration of movement of the core member, and means for opening and closing the circuit of the solenoid, said means being actuated by the core member in the uppermost position thereof to open said circuit.

5. A circuit controlling device comprising a solenoid including a cylinder and a core member operating therein, a pair of contacts mounted upon a support contiguous to the lower end of the solenoid and normally biased to relatively move into one of the circuit controlling positions, the movable contact being retained by the weight of the core member in the other of its positions to be released upon actuation of the core member, relatively movable contacts contiguous to the opposite end of the solenoid for closing and opening the circuit thereof and normally biased to move to circuit closing position, a releasable detent for retaining the movable contact in circuit opening position, and an armature on the movable contact actuated when the core member reaches its uppermost position to move said movable contact into locking engagement with said detent.

6. A circuit controlling device comprising a solenoid including a cylinder and a core member operating therein, a pair of contacts contiguous to the lower end of the solenoid including a spring contact retained in one position by the weight of the core member and moving to its other position upon the release thereof upon actuation of the core member, means for closing and opening the circuit of the solenoid, said means including an armature attracted by the core member in the uppermost position to open the circuit, and a detent for locking the contact in circuit opening position, and means for venting said cylinder as the core member moves into and from engagement with said first mentioned movable contact, said venting means being closed by said core member during travel thereof in both directions in the upper position of the cylinder to increase the retarding action.

FAIRFIELD W. HOBAN. 

